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πŸ”— The Centipede’s Dilemma

πŸ”— Psychology πŸ”— Poetry

"The Centipede's Dilemma" is a short poem that has lent its name to a psychological effect called the centipede effect or centipede syndrome. The centipede effect occurs when a normally automatic or unconscious activity is disrupted by consciousness of it or reflection on it. For example, a golfer thinking too closely about their swing or someone thinking too much about how they knot their tie may find their performance of the task impaired. The effect is also known as hyperreflection or Humphrey's law after English psychologist George Humphrey (1889–1966), who propounded it in 1923. As he wrote of the poem, "This is a most psychological rhyme. It contains a profound truth which is illustrated daily in the lives of all of us". The effect is the reverse of a solvitur ambulando.

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πŸ”— Elon Musk's Tesla Roadster

πŸ”— United States πŸ”— Spaceflight πŸ”— Automobiles

Elon Musk's Tesla Roadster is an electric sports car that served as the dummy payload for the February 2018 Falcon Heavy test flight and became an artificial satellite of the Sun. "Starman", a mannequin dressed in a spacesuit, occupies the driver's seat. The car and rocket are products of Tesla and SpaceX, respectively, both companies founded by Elon Musk. The 2008-model Roadster was previously used by Musk for commuting to work and is the only production car in space.

The car, mounted on the rocket's second stage, acquired enough velocity to escape Earth's gravity and enter an elliptical heliocentric orbit crossing the orbit of Mars. The orbit reaches a maximum distance from the Sun at aphelion of 1.66 astronomical units (au). During the early portion of the voyage outside the Earth's atmosphere, live video was transmitted back to the mission control center and live-streamed for slightly over four hours.

Advertising analysts noted Musk's sense of brand management and use of new media for his decision to launch a Tesla into space. While some commenters voiced concern that the car contributed to space debris, others saw it as a work of art. Musk explained he wanted to inspire the public about the "possibility of something new happening in space" as part of his larger vision for spreading humanity to other planets.

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πŸ”— Hallucinogenic Fish

πŸ”— Fishes πŸ”— Psychoactive and Recreational Drugs πŸ”— Altered States of Consciousness

Several species of fish are claimed to produce hallucinogenic effects when consumed. For example, Sarpa salpa, a species of sea bream, is commonly claimed to be hallucinogenic. These widely distributed coastal fish are normally found in the Mediterranean and around Spain, and along the west and south coasts of Africa. Occasionally they are found in British waters. They may induce hallucinogenic effects that are purportedly LSD-like if eaten. In 2006, two men who apparently ate the fish experienced hallucinations lasting for several days. The likelihood of hallucinations depends on the season. Sarpa salpa is known as "the fish that makes dreams" in Arabic.

Other species claimed to be capable of producing hallucinations include several species of sea chub from the genus Kyphosus. It is unclear whether the toxins are produced by the fish themselves or by marine algae in their diet. Other hallucinogenic fish are Siganus spinus, called "the fish that inebriates" in Reunion Island, and Mulloidichthys flavolineatus (formerly Mulloidichthys samoensis), called "the chief of ghosts" in Hawaii.

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πŸ”— Status-6 Oceanic Multipurpose System (Poseidon)

πŸ”— Military history πŸ”— Military history/Military science, technology, and theory πŸ”— Military history/Weaponry πŸ”— Military history/Russian, Soviet and CIS military history πŸ”— Military history/Post-Cold War

The Poseidon (Russian: ПосСйдон, "Poseidon", NATO reporting name Kanyon), previously known by Russian codename Status-6 (Russian: Бтатус-6), is an autonomous, nuclear-powered, and nuclear-armed unmanned underwater vehicle under development by Rubin Design Bureau, capable of delivering both conventional and nuclear payloads.

The Poseidon is one of the six new Russian strategic weapons announced by Russian President Vladimir Putin on 1Β MarchΒ 2018.

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πŸ”— _NSAKEY

πŸ”— Computer Security πŸ”— Computer Security/Computing πŸ”— Microsoft Windows πŸ”— Microsoft Windows/Computing πŸ”— Cryptography πŸ”— Cryptography/Computer science

_NSAKEY was a variable name discovered in an operating system from Microsoft in 1999. The variable contained a 1024-bit public key; such keys are used in cryptography for encryption and authentication. Due to the name it was speculated that the key was owned by the United States National Security Agency (the NSA) which would allow the intelligence agency to subvert any Windows user's security. Microsoft denied the speculation and said that the key's name came from the NSA being the technical review authority for U.S. cryptography export controls.

The key was discovered in a Windows NT 4 Service Pack 5 (which had been released unstripped of its symbolic debugging data) in August 1999 by Andrew D. Fernandes of Cryptonym Corporation.

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πŸ”— El Ajedrecista

πŸ”— Chess

El Ajedrecista (English: The Chess Player) is an automaton built in 1912 by Leonardo Torres y Quevedo, one of the first autonomous machines capable of playing chess. As opposed to the human-operated The Turk and Ajeeb, El Ajedrecista was a true automaton built to play chess without human guidance. It played an endgame with three chess pieces, automatically moving a white king and a rook to checkmate the black king moved by a human opponent.

The device could be considered the first computer game in history. It created great excitement when it made its debut, at the University of Paris in 1914. It was first widely mentioned in Scientific American as "Torres and His Remarkable Automatic Devices" on November 6, 1915.

The automaton does not deliver checkmate in the minimum number of moves, nor always within the 50 moves allotted by the fifty-move rule, because of the simple algorithm that calculates the moves. It did, however, checkmate the opponent every time. If an illegal move was made by the opposite player, the automaton would signal it by turning on a light. If the opposing player made three illegal moves, the automaton would stop playing.

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πŸ”— P versus NP

πŸ”— Computing πŸ”— Computer science πŸ”— Mathematics

The P versus NP problem is a major unsolved problem in computer science. It asks whether every problem whose solution can be quickly verified can also be solved quickly.

It is one of the seven Millennium Prize Problems selected by the Clay Mathematics Institute, each of which carries a US$1,000,000 prize for the first correct solution.

The informal term quickly, used above, means the existence of an algorithm solving the task that runs in polynomial time, such that the time to complete the task varies as a polynomial function on the size of the input to the algorithm (as opposed to, say, exponential time). The general class of questions for which some algorithm can provide an answer in polynomial time is called "class P" or just "P". For some questions, there is no known way to find an answer quickly, but if one is provided with information showing what the answer is, it is possible to verify the answer quickly. The class of questions for which an answer can be verified in polynomial time is called NP, which stands for "nondeterministic polynomial time".

An answer to the PΒ =Β NP question would determine whether problems that can be verified in polynomial time can also be solved in polynomial time. If it turned out that PΒ β‰ Β NP, which is widely believed, it would mean that there are problems in NP that are harder to compute than to verify: they could not be solved in polynomial time, but the answer could be verified in polynomial time.

Aside from being an important problem in computational theory, a proof either way would have profound implications for mathematics, cryptography, algorithm research, artificial intelligence, game theory, multimedia processing, philosophy, economics and many other fields.

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πŸ”— Electrodynamic Tether

πŸ”— Spaceflight πŸ”— Physics

Electrodynamic tethers (EDTs) are long conducting wires, such as one deployed from a tether satellite, which can operate on electromagnetic principles as generators, by converting their kinetic energy to electrical energy, or as motors, converting electrical energy to kinetic energy. Electric potential is generated across a conductive tether by its motion through a planet's magnetic field.

A number of missions have demonstrated electrodynamic tethers in space, most notably the TSS-1, TSS-1R, and Plasma Motor Generator (PMG) experiments.

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πŸ”— Fruit machine (homosexuality test)

πŸ”— Human rights πŸ”— Canada πŸ”— LGBT studies πŸ”— Law Enforcement πŸ”— Discrimination

"Fruit machine" is a term for a device developed in Canada by Frank Robert Wake that was supposed to be able to identify gay men (derogatorily referred to as "fruits"). The subjects were made to view pornography; the device then measured the diameter of the pupils of the eyes (pupillary response test), perspiration, and pulse for a supposed erotic response.

The "fruit machine" was employed in Canada in the 1950s and 1960s during a campaign to eliminate all gay men from the civil service, the Royal Canadian Mounted Police (RCMP), and the military. A substantial number of workers did lose their jobs. Although funding for the "fruit machine" project was cut off in the late 1960s, the investigations continued, and the RCMP collected files on over 9,000 "suspected" gay people.

The chair employed resembled that used by dentists. It had a pulley with a camera going towards the pupils, with a black box located in front of it that displayed pictures. The pictures ranged from the mundane to sexually explicit photos of men and women. It had previously been determined that the pupils would dilate in relation to the amount of interest in the picture per the technique termed 'the pupillary response test'.

People were first led to believe that the machine's purpose was to rate stress. After knowledge of its real purpose became widespread, few people volunteered for it.

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πŸ”— Hyperbolic Discounting

πŸ”— Economics πŸ”— Philosophy πŸ”— Philosophy/Logic

In economics, hyperbolic discounting is a time-inconsistent model of delay discounting. It is one of the cornerstones of behavioral economics and its brain-basis is actively being studied by neuroeconomics researchers.

The discounted utility approach states that intertemporal choices are no different from other choices, except that some consequences are delayed and hence must be anticipated and discounted (i.e., reweighted to take into account the delay).

Given two similar rewards, humans show a preference for one that arrives sooner rather than later. Humans are said to discount the value of the later reward, by a factor that increases with the length of the delay. In the financial world, this process is normally modeled in the form of exponential discounting, a time-consistent model of discounting. A large number of psychological studies have since demonstrated deviations in instinctive preference from the constant discount rate assumed in exponential discounting. Hyperbolic discounting is an alternative mathematical model that agrees more closely with these findings.

According to hyperbolic discounting, valuations fall relatively rapidly for earlier delay periods (as in, from now to one week), but then fall more slowly for longer delay periods (for instance, more than a few days). For example, in an early study subjects said they would be indifferent between receiving $15 immediately or $30 after 3 months, $60 after 1 year, or $100 after 3 years. These indifferences reflect annual discount rates that declined from 277% to 139% to 63% as delays got longer. This contrasts with exponential discounting, in which valuation falls by a constant factor per unit delay and the discount rate stays the same.

The standard experiment used to reveal a test subject's hyperbolic discounting curve is to compare short-term preferences with long-term preferences. For instance: "Would you prefer a dollar today or three dollars tomorrow?" or "Would you prefer a dollar in one year or three dollars in one year and one day?" It has been claimed that a significant fraction of subjects will take the lesser amount today, but will gladly wait one extra day in a year in order to receive the higher amount instead. Individuals with such preferences are described as "present-biased".

The most important consequence of hyperbolic discounting is that it creates temporary preferences for small rewards that occur sooner over larger, later ones. Individuals using hyperbolic discounting reveal a strong tendency to make choices that are inconsistent over time – they make choices today that their future self would prefer not to have made, despite knowing the same information. This dynamic inconsistency happens because hyperbolas distort the relative value of options with a fixed difference in delays in proportion to how far the choice-maker is from those options.